Why the LT4 ??
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From: Arizona
Why the LT4 ??
I was thinking about this the other night. Why did GM go through the expense of R&D and tooling to produce the LT4 for only 1 year?
I certainly see the advantages of the motor and am guessing they may have offered it in another car, but again why in the first place and why so short lived?
I certainly see the advantages of the motor and am guessing they may have offered it in another car, but again why in the first place and why so short lived?
Racer
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From: Kalamazoo MI
They were probably ready to go with the LS1 engine by then. I know development started for the next generation small block in 1991. By 1993 decided they couldn't just improve on the LTx small blocks and that the Flint assembly plant was too expensive to retool, so they had to come up with a whole new engine thus the LSx series (and built a new plant). What improvements they already had on the LT1 up to that point went into the LT4. I'd also like to believe they wanted to do something special for the last year of the C4's. Wasn't something similar done for the C3? Too bad they didn't have a Grand Sport C5.
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Originally Posted by k99ja04
They were probably ready to go with the LS1 engine by then. I know development started for the next generation small block in 1991. By 1993 decided they couldn't just improve on the LTx small blocks and that the Flint assembly plant was too expensive to retool, so they had to come up with a whole new engine thus the LSx series (and built a new plant). What improvements they already had on the LT1 up to that point went into the LT4. I'd also like to believe they wanted to do something special for the last year of the C4's. Wasn't something similar done for the C3? Too bad they didn't have a Grand Sport C5.
Jared
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From: Littleton CO
Originally Posted by Bobalooo
...the expense of R&D and tooling...
.
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Originally Posted by k99ja04
They were probably ready to go with the LS1 engine by then. I know development started for the next generation small block in 1991. By 1993 decided they couldn't just improve on the LTx small blocks and that the Flint assembly plant was too expensive to retool, so they had to come up with a whole new engine thus the LSx series (and built a new plant). What improvements they already had on the LT1 up to that point went into the LT4. I'd also like to believe they wanted to do something special for the last year of the C4's. Wasn't something similar done for the C3? Too bad they didn't have a Grand Sport C5.
Jared
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From: Athens AL
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82 was a crossfire, yes.
GM had to tool up the LT1 in its last year of production because most of the information about the C5 was already out, and they wanted to give people a reason to buy the 96s, so they bumped up the power. GM usually does this when they know people will just wait to buy the newer, improved model.
GM had to tool up the LT1 in its last year of production because most of the information about the C5 was already out, and they wanted to give people a reason to buy the 96s, so they bumped up the power. GM usually does this when they know people will just wait to buy the newer, improved model.
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From: San Pedro CA
Originally Posted by JCD
The last C3 had the crossfire, right? They carried that over to the '84 then upgraded again in '85?
Quick, someone do some research....
Quick, someone do some research....
The C5 was supposed to have the LT5 in it. But GM nixed idea as expensive.
The Vortec truck engine is directly related to the LSx series of motors. They share structure and internal design, however, their tasks are totally different. One is a truck motor, one is a sports car motor.
The LT4 was done as a last hurrah for the original SBC. It was used in the 1996 Vette and about 100 1997 Camaro Z28 SS models.
There was no other reason than to say good by to the original SBC design.
I don't view the Vortec and LSx family of engines as being small blocks, tho... they are different animals... no parts interchange...
BTW, the big 8.1 litre truck Vortec? That's actually a Mark IV 454 bored out.
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Melting Slicks
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From: Austin Texas
Originally Posted by bogus
yes, so what's the question?
The LT4 was done as a last hurrah for the original SBC. It was used in the 1996 Vette and about 100 1997 Camaro Z28 SS models.
The LT4 was done as a last hurrah for the original SBC. It was used in the 1996 Vette and about 100 1997 Camaro Z28 SS models.
what are the published HP and Torque specs for the LT-4?
inquiring blogger wants to know!
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From: eville in
Originally Posted by MikeC4
did all '96's come with the LT-4, or was this an option, with the LT-1 as base?
what are the published HP and Torque specs for the LT-4?
inquiring blogger wants to know!
what are the published HP and Torque specs for the LT-4?
inquiring blogger wants to know!
Melting Slicks
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From: If you don't weigh in you don't wrestle Road America
The LT-4 was an option and the published hp was 330hp and torque was at 350 ft/lb.
The Corvette has always done something to say goodbye to a generation. The 67 was definatley the best of the mid-years (mostly interior changes) In 1982 they did the cross-fire (not sure if that is exactly a bonus or not? Sorry any x-fire lovers if there are any
. Then in 1996 they did the LT-4, I also read that Chevy wanted to continue to have two engine options and since they ran out of LT-5's they made the LT-4's. But the biggest reason was for people like us to have something to talk about. 
The Corvette has always done something to say goodbye to a generation. The 67 was definatley the best of the mid-years (mostly interior changes) In 1982 they did the cross-fire (not sure if that is exactly a bonus or not? Sorry any x-fire lovers if there are any
. Then in 1996 they did the LT-4, I also read that Chevy wanted to continue to have two engine options and since they ran out of LT-5's they made the LT-4's. But the biggest reason was for people like us to have something to talk about.
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From: Hinckley Ohio
Last hurrah for the C4.......yes
Something special..Grand Sport to get people to buy........yes
But I think significantly the LT4 was a result of GM's struggle to determine if it was going to continue with tradition or change direction to LT5 type overhead cam engines.........obviously it has turned out that the "traditional" small block tradition has continued with Corvette......in the early 90's the committment to the traditional small block was being seriously challenged by small efficient dual overhead cam engines...lot of speculation a C5 would be mid-engine or ????
Legend now is the GM engineers did too good of a job with the LT4........possibly the hot cam was planned for production, 52mm throttle body, significance of mismatch ofthe head/intake ports......all suggest the LT4 was tamed by the marketing dept at the last minute...my bet is it was making more hp than the LT5,probably more than 400, with lower cost/better mpg etc...
Still an interesting question...why didn't they just wait for the C5.......and go with the LS1........
Something special..Grand Sport to get people to buy........yes
But I think significantly the LT4 was a result of GM's struggle to determine if it was going to continue with tradition or change direction to LT5 type overhead cam engines.........obviously it has turned out that the "traditional" small block tradition has continued with Corvette......in the early 90's the committment to the traditional small block was being seriously challenged by small efficient dual overhead cam engines...lot of speculation a C5 would be mid-engine or ????
Legend now is the GM engineers did too good of a job with the LT4........possibly the hot cam was planned for production, 52mm throttle body, significance of mismatch ofthe head/intake ports......all suggest the LT4 was tamed by the marketing dept at the last minute...my bet is it was making more hp than the LT5,probably more than 400, with lower cost/better mpg etc...
Still an interesting question...why didn't they just wait for the C5.......and go with the LS1........
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Originally Posted by MikeC4
did all '96's come with the LT-4, or was this an option, with the LT-1 as base?
what are the published HP and Torque specs for the LT-4?
inquiring blogger wants to know!
what are the published HP and Torque specs for the LT-4?
inquiring blogger wants to know!
330 and 350, but the LT4 is underrated because of the LS1 to come out in the 97. LS1 puts out 345 in its early years, but the LT4 actually puts out 350 HP at the crank, GM purposely underrated it.
Racer
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From: triangle NC
I love traditional small blocks, but I am tired of hearing the lt4 was underrated because of the ls1. Thats a bunch of crap. I am sure the lt4 is underrated because of averages, but thats another story. The traditional small block cant whipe the lsx's ***. It is a far superior design in many ways. The cylinder heads are 15 deg compared to 23, and are more efficient through higher velocity just to name one. The gen 4 ls7 heads are 12 deg 
and it uses titanium connecting rods! That is going to be an insane factory engine. I love my c4 but if I had the coin I would jump on a c6 z06 like no tomorrow.
and it uses titanium connecting rods! That is going to be an insane factory engine. I love my c4 but if I had the coin I would jump on a c6 z06 like no tomorrow.
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From: No more yankee my wankee, the Donger is tired!
Originally Posted by LT4BUD
all suggest the LT4 was tamed by the marketing dept at the last minute...my bet is it was making more hp than the LT5,probably more than 400, with lower cost/better mpg etc...
Im, sure the marketing dept cared. The LT5 program had been dead since 93. GM's main concern was the LS1 being a higher horse variant than the model it replaced. You don't sell a 300 horse engine one year and come out with a all new one producing 275 the following year.
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From: Bon Aqua tn
check out www.grandsportregistry.com they have the specs and diffrences bettween the lt1 and lt4 we got a good deal for the 1500 option when you see what it all includes. steel crank.sodium filled valves.forged rods..ect check it out for yourself its an interesting read.
Last edited by rockindaves96; Jan 19, 2005 at 12:12 AM.
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From: San Pedro CA
Originally Posted by 87Z-ya
I love traditional small blocks, but I am tired of hearing the lt4 was underrated because of the ls1. Thats a bunch of crap. I am sure the lt4 is underrated because of averages, but thats another story. The traditional small block cant whipe the lsx's ***. It is a far superior design in many ways. The cylinder heads are 15 deg compared to 23, and are more efficient through higher velocity just to name one. The gen 4 ls7 heads are 12 deg and it uses titanium connecting rods! That is going to be an insane factory engine. I love my c4 but if I had the coin I would jump on a c6 z06 like no tomorrow.
and it uses titanium connecting rods! That is going to be an insane factory engine. I love my c4 but if I had the coin I would jump on a c6 z06 like no tomorrow.If you ever read the book, "Corvette from the Inside" by Dave McClellen, it is rather obvious that the LT4 was underrated.
GM had a hell of a problem (so did all automakers) telling the consumer that 340hp is really the same as 450hp, when they went from SAE gross to net ratings.
An all new Vette was being released, and it had to be better, in all facets, than the prior version. That meant, it had to have more power than the base model it replaced. The engine was new, the drivetrain, the chassis, everything.
If variances were the reason, just about every one here that has been tested on a chassis dyno tell the tale... They are all testing in the 300hp range, or more, and with a 15% error rate, that works out to 350hp.